What is the Association With Dissociation?—Reply

In Reply We thank Kappler and colleagues for their interest in our article.¹ Our study showed an association of increased hospital mortality rates in patients with hypercapnic acidosis, and such an association with increased mortality rates was not seen in patients with compensated hypercapnia irrespective of increasing partial pressure of carbon dioxide (Pco₂).¹ The cohort of patients with hypercapnic acidosis had higher Acute Physiologic Assessment and Chronic Health Evaluation and Simplified Acute Physiology scores, suggesting that they had higher illness severity. While we have adjusted for several known confounders, including illness severity, the propensity to be hypercapnic, the propensity to be hypercapnic acidotic, baseline Glasgow Coma Scale, and the year of patient’s admission, there could be other unknown confounders that may have accounted for the observed differences in the outcomes. We have highlighted this as a limitation of the study.¹ Nevertheless, to our knowledge, the study is the largest study published so far on evaluating the association of hypercapnia in conjunction with pH levels on important clinical outcomes.